Genetic Crosses that Involve 2 Traits -- Biology 2
In rabbits, grey hair is dominant to white hair.
Also in rabbits, black eyes are dominant to red eyes.
These letters represent the genotypes of the rabbits:
GG = gray hair
Gg = gray hair
gg = white hair
BB = black eyes
Bb = black eyes
bb = red eyes
1. What are the phenotypes (descriptions) of rabbits that have the following genotypes:
Ggbb ____________________ ggBB ________________________
ggbb ____________________ GgBb _________________________
2. A male rabbit with the genotype GGbb is crossed with a female rabbit with the
genotype ggBb The square is set up below. Fill it out and determine the phenotypes and
proportions in the offspring.
How many out of 16 have grey fur
and black eyes? ________
How many out of 16 have grey fur
and red eyes? ________
How many out of 16 have white
fur and black eyes? ________
How many out of 16 have white
fur and red eyes? ________
3. A male rabbit with the genotype GgBb is crossed with a female rabbit with the
genotype GgBb The square is set up below. Fill it out and determine the phenotypes and
proportions in the offspring.
How many out of 16 have grey
fur and black eyes? ________
How many out of 16 have grey
fur and red eyes? ________
How many out of 16 have white
fur and black eyes? ________
How many out of 16 have white
fur and red eyes? ________
4. Show the cross between a ggBb and a GGBb. You'll have to set the square up yourself!